Power modules are known in the art and used as switches or rectifiers in power electronic circuits for controlling the power flow from a generator of a renewable power generating unit to the electrical grid.
The application in which the power modules are used may produces power and the closer to design limits the more power may be produced.
Such power modules can be protected by the way they are controlled i.e. most likely the lifetime of a power module which has been controlled close to its design limits are shorter than a power module which has been controlled according to an operation margin or safety margin which is lower than the design limit. In other words overload capabilities are limited by predefined current-time pattern which means large operation margin for overload.
International patent application WO 99/19974 A2 describes a power application circuit utilizes microelectromechanical (MEM) switches to reduce power loss in energy conversion equipment having a gate drive controlling the MEM switch.
In addition the state of the art includes the following patent applications. US patent application US 2010/0066337 A1 describes a power converter comprising a controller configured to estimate a terminal voltage of the power converter. European patent application EP2469710 A1 describes a power switch current estimator at a gate driver. US patent application US 2011/0058296 A1 describes a method of detecting a fault condition of a load device controlling the amount of power delivered to an electrical load. International patent application WO 2006/102930 A1 describes an electronic switch circuit connected to control means, a detector sensing current flow at terminals of the electronic switch and means for monitoring offset error of the detector.